The seven-time champion called on the All England Club to "loosen up the grip" on a rule that has been strictly enforced this year, leading to accusations of players even having their underwear checked before matches.

Former women's world number one Caroline Wozniacki said that was a "pretty creepy" prospect, and it falls at the extreme end of any action that may have been taken.

Where there has been some leeway afforded in previous years, players have been forcefully reminded of the tournament's 10-point clothing and equipment policy during the current fortnight. The rules call for "suitable tennis attire that is almost entirely white".